Re: [cocci] [PATCH -mm] -funsigned-char, x86: make struct p4_event_bind::cntr signed array

From: Julia Lawall <julia.lawall@inria.fr>
To: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: Kees Cook <keescook@chromium.org>,
	cocci@inria.fr, Linus Torvalds <torvalds@linux-foundation.org>,
	Alexey Dobriyan <adobriyan@gmail.com>,
	akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
	mm-commits@vger.kernel.org, masahiroy@kernel.org,
	gregkh@linuxfoundation.org, andriy.shevchenko@linux.intel.com,
	Stephen Rothwell <sfr@canb.auug.org.au>
Subject: Re: [cocci] [PATCH -mm] -funsigned-char, x86: make struct p4_event_bind::cntr signed array
Date: Thu, 3 Nov 2022 13:57:26 +0100 (CET)	[thread overview]
Message-ID: <8e7bcf3-2d39-a9f2-f818-ec627e5d5c4e@inria.fr> (raw)
In-Reply-To: <CAHmME9o3BDe+s2QaT4X8jg+9cc9A-3iHWnL0WnFyqKcGuhahXQ@mail.gmail.com>

On Thu, 3 Nov 2022, Jason A. Donenfeld wrote:

> Hi Julia,
>
> On Thu, Nov 3, 2022 at 1:45 PM Julia Lawall <julia.lawall@inria.fr> wrote:
> > It should work now.
>
> Thanks!
>
> > However, without disable optional_qualifier, char is
> > still matching signed char.  If you think that should be changed, I can do
> > that.
>
> Does `optional_qualifier` disable other things that might be
> interesting to have? If so, maybe this is less than ideal? If not,
> maybe it doesn't matter?

Optional qualifier only allows a metavariable declared to have a certain
type to match an expression that has the same type with signed, const, or
verbatim in front of it.  Disabling it forces you to write our signed,
const etc explicitly when you want them.  So rules may becomes more
verbose.

julia

>
> Though, for what it's worth, gcc treats `char` as a separate type,
> even when using `-funsigned-char` or `-fsigned-char`.
>
> Jason
>